SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '937794784f6545755f95f5068a4f0b8ec175122c5b530505b4e866d2fec63517' 
  AND token = '/qsP1n5GgXR+nOFGSzP/GEoPJCzD5nAY199C98dvO/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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