SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29250aa1367b18c6c5d5b3634d2974bedc6fcf8dcbd2881220c9addecaf3d4c5' 
  AND token = 'ovSRl71v0SYmTnn3vzsCBpiu7d8hvyhjPqHyfObKgUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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