SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2ca819e87b673c089f98e4b918fc52d41b3eb3f40b2a84009e6bacae8880476' 
  AND token = '5eKASSVNJ+/k7pU3HnXAmeQjGnj6QdcjPtQjmVAGzCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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