SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8f6f5a80d3d82901e34f52f33711ab2251acf90d533737c648c9286d255a2db' 
  AND token = 'ZBm5gk48N1wPeOy/IjbDDRJnAAWdxuovrhmGUtq/t78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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