SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f02551bc65af181a58ba0e9ed5fd212d1ef36fcaed28226ac86ca240b9ab395' 
  AND token = 'oE1zMCZ7QR0qzwoqt1KEugSg5DMfZR+NBubdJkFvyYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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