SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82de5d6b2465a610fffcc38ce4e647a8eb6ee391b4cfd3765bcd10603f9d3c52' 
  AND token = 'pHTUJgTWqOBIAD6JLVEugXP+EFv6Mlrz1hiD8CtDmJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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