SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b2f2473f560ad63bb332258868e0a2b6800f8154bbbd41e78f40fd94f20e65f0' 
  AND token = '7VgLzQFEbKoBT1Q1IDeBShjjZKmULq5syDP8R6uv54c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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