SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6b2ff3658592de70aff9a8630bf9a6bd088a49c2949643dcdb058685f0a157a' 
  AND token = 'bxCezCmMQR5Q7kbGj3fU3fiqJPwRvpQuMerhjelMfXE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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