SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0faa5d58c1fc87429a3d240c87c32c560e8e0a742ac3bc163d3442a76908318c' 
  AND token = 'l9NNrmnPb+quX3d3FQsQb8i8T+hJYeKCHDtxrsWlHh0=' 
  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"
    }
  }
}