SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a910e88da89b371cb73b152c95b3a0b4c9f1565ebdfc1ccac8d072161a20334' 
  AND token = 'tzFdSG1XAj9syCz5Msn6+75gmTimG5yIltGv1Rlu/SU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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