SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '982257ef78f8bfa3670f17feabd98bd766d9c283730ecaa178d646b60e62283d' 
  AND token = 'ENrw5OGQCv2I9klScrYTFwmLmpw2Kr22dQRerthujNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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