SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1f3e78d0051a826710087dacac48bca0120dc875055715762e0a74fbac5e8e0' 
  AND token = 'lC5XZ5CiLGFAHKbbFo7MFP/QcgRckWLWYwpqiETSJuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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