SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '604e8c1b25d331347bef7728c5ba63b6ccf001413c240ac9fedd8036f0e2390f' 
  AND token = 'nuIUjysSESkyocw4pKsLVwer69P5x+MNkA472BwUASs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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