SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd35453c4731624a31bc4243ab3c20a551425bfa0258858415baec836b4910c37' 
  AND token = 'DAWx81jxa3wrR8e0jPetvF+foGdAlYsLo3JTguUwaMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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