SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0ad49b7d39f51a2fa8788893cd2eb208e88610e828fa5f6bd934ab54d233009' 
  AND token = 'MHZU0La5cBw+4hkv18FWYSOIqjZ2vz3BD7z3ooQwXxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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