SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '893b576c6ed7f05a637d30c5a419c3694905c2f53998cc56b73f9f0876b90e91' 
  AND token = 'fEfYRmsBCpqQ/sH/IsVBR2gef8iCxBuYMGLKNytVbzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}