SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '844cfa5c48a64f37663f1cdaf921071b2b5e189049bb5815587deb96c3195184' 
  AND token = '3KJEcYqwJ8pjpm2HPQzDQX/+f628VRXg4sXjYE97spo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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