SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24d18db845018a67b05455f9e821a71567dd75c505a5e9818b4423d0a9d9b1ac' 
  AND token = 'dMMyjzgOvoFoBqZFEGSXip1nGW8CNl6/nWaRRHakEkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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