SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de03004190249ce3a6ad5c22749e923baf9d514d0383334861ff1ab76b4a595b' 
  AND token = 'sJveUnHm2yXWJb/Y+XATbXFipzCIx17YUfi7+WUxIqk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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