SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c83ba99182b4232bae99714739584a529fcf80eb3278abdd326a02e464a5651' 
  AND token = 'cwGEACGDs3l7JXM+SDmTuTF+TSi0JTdm+spSWCchsms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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