SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fd950da58ffdddcb851cd125872d99fce167a2043850405d4f90b6353d9ff46' 
  AND token = 'pJb44qbcJiflxymSI/RY4GumVPlrWZMaknOTrj3lu+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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