SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4dc5d477aad84dc079ee54f26d810f30dcd8c5cb701e82b58c36f2535bf1cfe' 
  AND token = 'OWbvFgZ6szejOrsEMwPjzM2xFpuJKIJXl3Nw0c/oD3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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