SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd700e2c73e23db42bd27cd2209f64f45116aac7001176a7320085e4d6a5d790' 
  AND token = 'Zz/3Bqz2HUzr/Fp7DM2yt/B3DnWTvOPbbVy+ZpLP9D0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}