SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b372846ecb90815f6d9ac19158aa76c6d67ee919b048d70510754535c245273f' 
  AND token = '4TecCpfPewcBOllQPHbcK8bWOdiojA8CAG6bESaHIf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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