SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea886271be0110b07b50fe1b0246e04053a1faf694488da2a1871858be79eba2' 
  AND token = 'CYjdtcRJD/hclTKiczPPtlQwK5vJm7HHhvCT7brUxD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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