SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb979845629be3d81544270fd8bf15003cb5475eb109679f497a2cdb608bbc2e' 
  AND token = 'ObAfMITzz+ePNWVALR7uufgMekS2RAsyCFzHEhjUDas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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