SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82f064303724ea30e284cf294a905b543c3566e44c5e7adead6eb73a4cbfbf2b' 
  AND token = '6ig/jCJwcl0J9HAYcuNk+56/0QOr6ouEqddvyjFgqeM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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