SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37651a004ed6bd5451577a46ddbb25ed2ca70ab31e552377c873b9ccbc561c87' 
  AND token = 'MvraJeF5UFLb2yRnC+se1Zh6dcckGjtDPE+erJ7vOTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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